DDOS Attack Detection

A denial-of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a computer resource unavailable to its intended users. One common method of attack involves saturating the target (victim) machine with external communications requests, such that it cannot respond to legitimate traffic, or responds so slowly as to be rendered effectively unavailable.

Using the command given below you can find out the list ips which are doing DDOS to your server at a particular moment.

netstat -anp|grep tcp|awk '{print $5}'| cut -d : -f1 | sort | uniq -c | sort -n

Regards
Nobs